They used to use them as small screwdrivers - 3 cent silver and half dimes. Never seen one clipped. Maybe they wanted to make sure it was silver all the way through. Or it was accidental.
So this wasn't a cracked planchet that just got like this over time. Perhaps someone was testing some silver cutting shears in a drunken binge that made the newspapers for unheralded inebriation and the sluggard mentality of a dullard.
Back in my High School shop days ... and ever since when I needed something to fill a gap or raise from a surface for torching; we'd use dimes, quarters etc for that in any type of press, anvil work or vice. I still do from time to time ... you're welcome ...
Here is one from Kunker site, a beautifull Salzburg 4 Dukat from 1513, that was deliberately vandalized by some rich noble back in time it circulated. This "jackass" etched the "4" on coin. I guess, you could blame the mint master too, why pray tell would they not add the value marker on coin? They struck coins upto 50 Dukats (175g. AV) no value on coin. And they had the oddest coin values like 44/36/28/16/8/7/6 Dukaten.
The cut may have happened completely accidentally as well, possibly if something heavy and sharp fell onto the coin.